Government Watchdog Says SpaceX Falcon 9s Are Prone To Cracks (engadget.com) 139
An anonymous reader shares an Engadget article: SpaceX's Falcon 9 rockets apparently have a serious issue that could delay the company's manned missions. According to the Wall Street Journal, the Government Accountability Office investigated both Boeing and SpaceX -- the corporations that won NASA's space taxi contracts -- and found that Falcon 9's turbine blades suffer from persistent cracks. GAO's preliminary report says these turboblades' tendency to crack is a "major threat to rocket safety," since they pump fuel into Falcon 9's rocket engines. NASA's acting administrator Robert Lightfoot told the WSJ that government officials have known about the issue for months or even years. The agency even told SpaceX that the cracks are too much risk for manned flights. A spokesperson said SpaceX has "qualified [its] engines to be robust" to cracks, but it's now "modifying the design to avoid them altogether."
Funny (Score:4, Insightful)
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How all the positive stories about Tesla and SpaceX make reference to Elon but all the negative stories don't even mention him
That is because when there is good news, Elon is front and center to deliver it himself. When there is bad news, it is buried in paragraph 3 of some PR webpage.
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the negative stories don't even mention him
It should - he was just tweeting recently that the block 5 Falcon was making reliability improvements (this) and that man-rated would wait for those.
Not sure how you get more upfront in 140 characters.
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Maybe because many positive things about Tesla and SpaceX are his ideas and his tweets, but many negative things are just hyperbole or standard operational issues ... like NASA saying there's a problem in an engine and SpaceX needing to fix it. Why would you need to quote Elon Musk for that? He has provided nothing to quote on.
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They have found some cracks and are dealing with the problem.
Anyone who expects prototypes to be born perfect is either deluded or an economist.
This is not a serious issue. This is very minor (Score:5, Informative)
Falcon 9 and the space shuttle are the only rockets whose engines have survived the launch so that they could have been inspected. And similar cracks have been found on shuttle engines too. Many other rocket engines very probbly have generated similar cracks during their burn, but those have not been inspected because the engines have gone to the bottom of the ocean.
There have been 28 launches of falcon. During those 28 launches, 279 Merlin 1-series engines have been used, with only 1 major engine problem. And even in that case, the rocket delivered the primary payload to the desired orbit; Each falcon 9 has 10 engines and only on of those 10 engines is critical whose failure leads to mission failure.
So, until now, the engines have had 99.64% reliability, and due the engine redundancy, only 10% of engine failures means mission failure on most launches(upper stage engine may not fail), meaning mission failure probability of 0.04% due failing engine if the engines keep working equally well in the future than they previously have been working.
No, the this turbine thing is not a big problem. Bigger problems are elsewhere, and spaceX is improving the turbine blades. They will continue launching the version with the weak turbine blanes for some time, and it's very unlikely it will cause ANY problems at all, and then later the will release the block 5 model of the rocket with more robust turbine blades.
It seem that the whole issue is "leaked" by some guy who is pissed to spaceX/Elon for something and the media is always eager to post this kind of "leaks" without really understanding what it is all about.
Re:This is not a serious issue. This is very minor (Score:4, Informative)
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Re:This is not a serious issue. This is very minor (Score:5, Informative)
Plenty of other engines have been inspected on the ground after running one or more full flight cycles on engine test stands (like every engine ever used), so there is actually data on more engine types than just those two. The damage comes from the part where they run the turbines at ludicrous speed for several minutes, not the fact that they re-enter
Standards when a human is on board are way more stringent than for cargo. They have to meet an overall 1 in 500 probability of failure during ascent, and it sounds like the blades are bad enough that that hurts them on meeting this requirement.
That being said, there are plenty of other parts I'm worried about, like structural failures in fuel tanks (they've had two of those that have actually destroyed rockets).
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Standards when a human is on board are way more stringent than for cargo. They have to meet an overall 1 in 500 probability of failure during ascent
Are you sure? Ars mentions "NASA's mission requirement for a loss-of-crew probability of 1-in-270" -- presumably "mission requirement" covers ascent, orbit and descent.
https://arstechnica.com/scienc... [arstechnica.com]
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Loss of a blade certainly means shutdown of the engine. This is normal, accepted, and accounted for. It has happened before on a Falcon 9 flight (shutdown of an engine, I mean, I don't know if a blade was thrown). It also happened during Apollo 13's second stage burn.
Even if the entire rocket was lost, it STILL doesn't mean loss of life. All manned rockets I'm aware of (and I'm not a rocket scientist or even a particularly devoted follower of rocketry) have launch escape systems, and they get tested; the on
Re:This is not a serious issue. This is very minor (Score:4, Interesting)
That's actually a much higher safety rating than NASA'a man rating requirement. It is also a much higher safety rating than any manned system to date.
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No, I think you do.
1) Mission failure does not mean explosion; it means mission failure. Aka, you fail to reach the desired orbit.
2) Explosion does not mean death; Dragon has a launch escape system, unlike the Shuttle.
3) Even if that was "0,04% chance of death", that would be an exceedingly low rate by spaceflight standards.
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Why don't you share how horrible a 0.04% launch failure rate is.
Let me help, that's 1 failure every 2500 launches. If there were 5 people on board and they launched 100 rockets per year that would mean an average of 1/5th of a death per year.
And that statistic doesn't take into account the crew capsule escape mechanism.
About 2 million people a year die in the US.
Go see how many astronauts have died in car accidents. None in a Tesla, so far.
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Yep. With non-recoverable rockets that end up on the ocean floor, we never know if the rocket engines were consistently on the edge of catastrophic failure. Without looking at the used engines, the only thing we really know about expendable rockets is that they generated nominal telemetry during operation.
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Yes. If only they did some kind of testing with those rocket engines so they could evaluate their performance before they launched them.....like maybe put them on a test stand and run them and then take them apart to see how they did.
Very worthwhile testing no doubt but still a pale substitute for actually launching & retrieving them
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In regard to cracks caused by the pressure and heat of the fuel when ignited, or of the turbineblades which pump the fuel, etc., it gives an exact representation, not a 'pale substitute'. There are some form of stresses that are less accurate when measured on ground-tests, but most of it provides excellent proof of reliability (or lack thereof) at the same level as if the rocket *were* retrieved afterwards.
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>Falcon 9 and the space shuttle are the only rockets whose engines have survived the launch
Not true. 11F35's RD170s were recovered after parachute landing and are still standing at Energomash museum. First standalone Zenit launches were also all recovered. All Russian engines has to be test fired multiple times prior to launch. Yes, even beryllium/H2O2 sludge and B5H9 + ClF5 burning wunderwaffes like RD270M were test fired.
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Nothing to worry about (Score:5, Funny)
As Elon would say, the cracks may simply lead to Rapid Unscheduled Passenger Disembarkation.
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Rocket Science is Hard (Score:3)
I think somebody said that over the past year or so.
While an important safety issue, it's good that it is identified and plans are in place to fix them before the Falcon is considered man-rated.
Excelsior!
Can someone explain the turbine here? (Score:3)
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After exhaustive research and digging,some deep soul searching, and some visits to top rocket propulsion laboratories worldwide I have concluded that the summary states "they pump fuel into Falcon 9's rocket engines".
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It's part of the fuel pump. Turns out, injecting a hair under 400 tonnes of liquid oxygen and RP-1 into 95 atmosphere chambers over the course of three minutes takes quite a bit of doing, and the pumps to do that are much of what makes up a liquid fuel rocket engine.
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Yup. 97 bar is the chamber pressure of a merlin engine. The gain from combustion is basically a volume change, not a pressure change, so you /are/ pumping that up that pressure differential - the fuel at the pump is a much smaller volume than the fuel leaving the engine, so the mechanical energy input is much lower than the mechanical output (the power is the pressure x volume flow rate, which reduces down to force x velocity, the usual units for power). It's still huge, though. Even the parts of these mach
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I ask because, in jet engines, where the turbine blades are exposed to combustion temperatures, fabricating them is a considerable challenge because optimal operating temperatures are well above
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To get some perspective so is your lawn mower engine, but conduction through the Al-Si alloy block means that the parts don't get anywhere near the flame temperature.
Jet turbine blades get hot but still nothing like the flame temperature so nothing like the melting point of Inconel or the more modern alloys used - but they do get hot enough that the mechanical propertie
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Gases push them and they rotate to power the kerosene pump
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I'm not much better educated than yourself, but here's an attempt (which may be wrong):
The higher the pressure a combustion chamber runs at, the more efficient the combustion tends to be, so your rocket goes higher for a given amount of fuel. To get enough fuel into a high pressure chamber you need a good fuel pump. To drive this fuel pump, a gas turbine is used (the resulting fuel pump is called a "turbopump").
Inside the gas turbine, the turbine proper (the spinning fan-thingy at the back) is driven from
Re:Can someone explain the turbine here? (Score:4, Informative)
It's a fuel pump. Unlike a reciprocating engine, where you can inject the fuel at low pressure and then compress it, a rocket engine has to inject the propellant at the same pressure it's burned at, and thermodynamics wants that pressure to be as high as possible in order to get maximum efficiency (imagine a car engine that injected fuel at the top of the cylinder stroke instead of the bottom). Combined with the sheer amount of propellant being used, that means you need an absolutely insane amount of power in your fuel and oxidizer pumps.
So they use a turbopump. A small amount of fuel and oxidizer are tapped off and burned. The resulting hot CO2 and H2O are used to run a turbine, which drives the pump. In the Merlin engines, and in many other engines, it ends up just exhausting, generating no additional thrust. Other designs, including Raptor, find ways to re-use that exhaust to generate a bit more power.
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tantamount to treason. (Score:2)
That's insane.
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No, I suggested that a current rocket, that is currently in use, uses a very reliable engine (and is currently routinely used to launch our critical defense infrastructure - more often that it's US made competitors right now) and will also be used to launch humans in the next couple of years.
Please address all complaints about the current status to your congressman...
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I'm pretty sure the engines we buy from Russia post-date the Soviet Union.
Not by much:
https://en.wikipedia.org/wiki/RD-180
It's a scaled down version of a Soviet Union rocket engine (RD-170).
On the other hand these ones don't (Score:2)
https://en.wikipedia.org/wiki/... [wikipedia.org]
Take a look at the section on "design" here:
https://en.wikipedia.org/wiki/... [wikipedia.org]
Yet that is not a problem. Just news ink... (Score:2)
Also GAO does not find technical problems....
Spacex and Nasa found it, a long time ago.
GAO only predicts it can be a cause for delays beyond 2018.
Apollo 13 blew up (Score:3)
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SpaceX's planned endgame will have more payload to orbit than the SaturnV (Falcon XX heavy)
Right now there aren't such big rockets because there isn't a _need_ for them. I'd still like someone to build a Sea Dragon though.
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C'mon SpaceX (Score:2)
This is NASA, they're pretty anal about manned spaceflight. You damn well better engineer the turbines to get rid of the cracks.
There is a huge potential for savings with SpaceX's model for launching and reusing rockets, but it all collapses given just a few failures.
If they get very high reliability of their rockets, reuse will end up being a cost destroyer. If they blow some rockets up the reuse savings will disappear.
Not SpaceX (Score:2)
NASA (Score:2)
There is an easy solution to this. Do what NASA did for the Shuttle engines and redefine cracks in the turbines to be a maintenance problem instead of a flight safety problem.
Re:Musk always ignores safety (Score:5, Insightful)
He hasn't taken quality control seriously in any of his ventures, that is why they are all get-rich-quick schemes.
You want to back that up with... anything?
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No, you should try comprehending the abstract. Solid and liquid rocket motors are about as different as internal combustion engines and steam engines. Pointing to some generic study about some arbitrary solid rocket propellant as if that's supposed to mean anything whatsoever concerning a rocket that does not use solid rocket propellants of any kind just makes you look you don't know anything about the topic being discussed.
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Liquid rocket engines pump the cold fuel around the engine cone to simultaneously heat the fuel up and to keep the engine cool. You can shut down a liquid fuel engine, but once you've started up a solid fuel engine, it's impossible to shut down.
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lol
Commas, people... (Score:2)
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Just never greet your friend Jack in an airport, that can lead to uncomfortable questions.
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The report says you might need to drive autonomous vehicles 100's of millions of miles to have statistically valid conclusions. You sat "it is statistically impossible". At last report Tesla's were approaching 140 million miles.
You confuse whether you can show conclusive results due to sample size with whether something is or is not safer.
Tesla will likely have over 1 million vehicles on the road in the next 5 years and will be generating billions of miles per year. The sample size will be large enough t
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Exactly. when I read the article of his own link, it was clearly mentioned: "Under even aggressive testing assumptions, *existing* fleets would take tens and sometimes hundreds of years to drive these miles"
Maybe he didn't read the article well himself? Obviously, if one would have an 'existing fleet' of 1000 vehicles it could take tens of years, but if you have 1000000 vehicles you could have that within a couple of months.
I find it sometimes puzzling that people want to make a point , but than don't read
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Humans may not be able to "take over" but accidents were reduced according to the NHTSA investigation. So... that would mean humans being able to take over aren't necessary.
That being said, there are plenty of videos online of humans taking over so you're claim is patently false. Maybe they can't take over while watching Harry Potter but that's not the intended use.
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So an online video of one person taking over means all people have the att
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Autopilot is half baked.
The most advanced driver assist system ever released is half-baked, that government investigations have shown reduced the rate of crashes more than they caused? Thanks for the advice fluffer, your contribution was valuab.. sorry I couldn't finish that sentence.
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He doesn't have to his alternative facts stand on their own.
Only an enemy of the USA would question alternative facts.
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Re:Musk always ignores safety (Score:5, Insightful)
they are all get-rich-quick schemes.
1. He was already rich.
2. If he wanted to get richER, then an aerospace company would have been about the worst possible way to do that. Historically, aerospace tends to make large fortunes into small fortunes rather than the other way around.
Re:Musk always ignores safety (Score:5, Insightful)
2. If he wanted to get richER, then an aerospace company would have been about the worst possible way to do that.
Reminds me of the Richard Branson quote:
"If you want to be a Millionaire, start with a billion dollars and launch a new airline."
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I'm still waiting for him to announce that he is Iron Man...
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"If he wanted to get richER, then an aerospace company would have been about the worst possible way to do that"
And became the major backer and then the CEO of an AUTO company around the same time - another great way to turn a large fortune into a small one even if you weren't trying to make fully electric cars.
Re:Musk always ignores safety (Score:5, Funny)
I don't think you understand that aerospace is a very, very risky way to become richer.
If your goal is simply to become richer, being a asshole, owning a bunch of real estate and stiffing the people who work for you is a much more surefire method.
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> Or become President.
Or run unsuccessfully for president.
http://business.financialpost.... [financialpost.com] Leading up to the 2000 presidential election, Al Gore filed a financial report claiming a net worth of less than $2 million. Today he's worth $200 million. Let's just say those $100,000+ speaking fees didn't hurt.
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It's always a delight to see ULA shills here.
Let us know how reliable ULA's new rocket will be, once they actually have one they can launch.
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My understanding is that Space-X has not actually re-used any engines on a real flight to this point. They have only fired some of the returned ones on test pads. That means any cracks on a returned engine were from just one flight.
It's good engineering design to have it be able to survive a loss of an engine.
It's bad engineering design to have a known failure mode and not address it - especially if humans are going to be on board - even if the rocket can handle the loss.
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Sorry, this one was worn out within 24 hours of the first run.